The present invention relates to a device for dressing welding electrodes and in particular in automatic welding stations.
It is known that the electrodes which make contact with the sheet metal to be welded are the consumable part of a resistance welding system. For reasons of conductivity and contact resistance the electrodes must be made of nearly pure copper which is well known to be a ductile and malleable material. During use the electrodes are subject cyclically to high pressures with high temperatures and undergo a plastic deformation process which changes their shape to the detriment of welding quality. To limit deterioration of quality beyond acceptable limits in practice devices termed electrode dressers which periodically mill the upset material with small shaped milling cutters to restore the original shape of the electrode tip are used.
Since the dressers work by material removal they can only intervene a small number of times. The dressing operations are therefore spaced in time and between one operation and the next the quality of the welding tips undergoes progressive deterioration to the limit of acceptability. However, the dressers removing material shorten considerably the useful life of the electrodes with resulting increase in operating costs.
The general purpose of the present invention is to overcome the above mentioned drawbacks by making available a dressing device which could be used frequently with optimal results and without limiting the useful life of the electrodes.